Fatty Fronty - This thing is connected by the gastric system so, the front man will be the only one doing the eating. Each person still has their own stomach, so the only one really getting any nutrients from food is the front man. Also, I doubt this thing can move very well, so a whole lot of sitting and eating can lead to one big fatty.
Dead Middle - Doesn't eating poop kill you? I know German skat eaters can get away with swishing it around in their mouths, but doesn't trying to turn someone else's poop into your own poop open someone wormhole is time and kill you? Something like that. Plus talk about no nutritional value. Fatty McGee already sucked those up for himself. Bottom Line, whoever is in the middle is going to eat shit and die.
Imagine a hippo, sitting on dead Klaus Barbi, sitting on Ally Mcbeal. Just no good.
Aside from these overlooked details, I still want to see this movie. It might become my new favorite cheesy horror movie right after Night of the Creeps.